Missiles are commonly equipped with deployable flight control surfaces that provide aerodynamic guidance during flight. More recently, smaller projectiles (e.g., artillery shells) and modular components adapted to be mounted to smaller projectiles (e.g., fuse guidance kits) have also been equipped with deployable flight control surfaces. The deployable flight control surfaces often assume the form of a plurality of fins hingedly mounted to the projectile body. Each fin is rotatable between a non-deployed position, in which the fin resides against or within the projectile body, and a deployed position, in which the fin extends radially outward from the projectile body. Each fin is biased toward the deployed position by a mechanical biasing means (commonly referred to as a “deploy energy assembly”) and/or by centrifugal forces acting on the projectile as it spins during flight. In many cases, an onboard restraint system prevents the fins from rotating into the deployed position until the desired time of deployment, which may occur shortly after projectile launch or firing. Alternatively, the walls of a storage container may prevent the fins from rotating into the deployed position until the projectile is removed from the container. After the fins are released from the non-deployed position, the fins rotate toward the deployed position and are secured therein by an onboard locking mechanism. By initially maintaining the fins in a non-deployed position, the fins are protected from physical damage that might otherwise in the course of soldier handling. In addition, initial fin stowage allows denser packaging of airframes.
It is typically desirable for fin deployment to occur in an extremely abbreviated time frame; e.g., on the order of a few fractions of a second. Thus, to achieve rapid fin deployment, deploy energy assemblies conventionally utilize one or more springs that store a significant amount of potential energy in their deformed state and that rapidly accelerate each fin from the non-deployed position through the deployed position. While enabling rapid fin deployment, conventional deployment systems that rapidly accelerate the fin through the deployed position can be disadvantageous for two primary reasons. First, onboard locking mechanisms of the type described above typically rely on precision alignment between mating components, such as spring-loaded pins, to secure the fin in the deployed position. When the rotational speed of the fin through the deployed position is excessively high, the onboard locking mechanism may have difficulty engaging the rapidly-rotating fin, which may then rotate past the desired deployed position. Fin over-rotation impacts the desired aerodynamic effects of the flight control surface and typically cannot be corrected by conventional deploy energy assemblies, which provide a unidirectional bias through the deployed position. As a second disadvantage, when the rapidly-rotating fin is abruptly arrested in the deployed position by the onboard locking mechanism, a significant mechanical shock or disturbance is produced and emanates through the projectile. Such a mechanical shock can potentially damage auxiliary components onboard the projectile and/or introduce inaccuracies into projectile guidance.
There thus exists an ongoing need to provide embodiments of a deployment system suitable for utilization with projectiles (or other airborne object) that enables rapid deployment of flight control surfaces (or other deployable elements) while overcoming the above-noted limitations associated with conventional deployment systems. In particular, it would be desirable to provide embodiments of a deployment system that reliably locks flight control surfaces in a precise position during rapid deployment, that returns the flight control surfaces to the deployed position should over-rotation occur, and that minimizes disturbances generated when the flight control surfaces are secured in the deployed position. Other desirable features and characteristics of the present invention will become apparent from the subsequent Detailed Description and the appended Claims, taken in conjunction with the accompanying Drawings and this Background.